import sun.reflect.generics.tree.Tree;


import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;
import java.util.Queue;

public class BinaryTree {
    static class TreeNode{
        public char val ;
        public TreeNode left ;
        public TreeNode right ;

        public TreeNode(char val) {
            this.val = val;
        }

        @Override
        public String toString() {
            return "TreeNode{" +
                    "val=" + val +
                    '}';
        }
    }
    public TreeNode createTree() {    //创造一个二叉树
        TreeNode node1 = new TreeNode('A');
        TreeNode node2 = new TreeNode('B');
        TreeNode node3 = new TreeNode('C');
        TreeNode node4 = new TreeNode('D');
        TreeNode node5 = new TreeNode('E');
        TreeNode node6 = new TreeNode('F');
        TreeNode node7 = new TreeNode('G');
        TreeNode node8 = new TreeNode('H');
        node1.left = node2 ;
        node1.right = node3 ;
        node2.left = node4 ;
        node2.right = node5 ;
        node3.left = node6 ;
        node3.right = node7 ;
        node4.left = node8;
        return  node1 ;
    }

    //创建一颗二叉树， 并返回根结点 ；
    static int i = 0 ;
    public  TreeNode createTree(String str){
        TreeNode root = null ;
        if(i<str.length() && str.charAt(i) != '#'){
            root = new TreeNode(str.charAt(i));
            i ++ ;
            root.left = createTree(str);
            root.right = createTree(str) ;
        }else{
            i ++ ;
            return null ;
        }
        return root ;
    }
    //前序遍历
    public void preOrder(TreeNode root){
        if(root == null) return;
        System.out.print(root.val + "  ");
        preOrder(root.left);
        preOrder(root.right);
    }

    //中序遍历
    public void inOrder(TreeNode root){
        if(root == null) return;
        inOrder(root.left);
        System.out.print(root.val + "  ");
        inOrder(root.right);
    }

    //后序遍历
    public void postOrder(TreeNode root){
        if(root == null) return;
        postOrder(root.left);
        postOrder(root.right);
        System.out.print(root.val + "  ");
    }


    public static int nodeSize;

    /**
     * 获取树中节点的个数：遍历思路
     */
    public void size(TreeNode root) {
        if(root == null) return;
       nodeSize ++ ;
       size(root.left);
       size(root.right);
    }

    /**
     * 获取节点的个数：子问题的思路
     *
     * @param root
     * @return
     */
    public int size2(TreeNode root) {
      if(root == null) return 0 ;
        return size2(root.left) + size2(root.right)+1 ;
    }


    /*
     获取叶子节点的个数：遍历思路
     */
    public static int leafSize = 0;

    void getLeafNodeCount1(TreeNode root) {
        if(root == null) return; ;
        if(root.left == null && root.right == null){
            leafSize ++ ;
        }
        getLeafNodeCount1(root.left);
        getLeafNodeCount1(root.right);
    }

    /*
        获取叶子节点的个数：子问题
        */
    int getLeafNodeCount2(TreeNode root) {
        if(root == null) return 0 ;
        if(root.left == null && root.right == null){
            return 1 ;
        }
       return getLeafNodeCount2(root.left) + getLeafNodeCount2(root.right);
    }
    /*
   获取第K层节点的个数
    */
    int getKLevelNodeCount(TreeNode root, int k) {
        if(root == null || k < 1) return  0 ;
        if(k == 1) return 1 ;
        return getKLevelNodeCount(root.left , k-1) +
                getKLevelNodeCount(root.right , k -1) ;
    }
    /*
    获取二叉树的高度
    时间复杂度：O(N)
    */
    int getHeight(TreeNode root) {
        if(root == null) return  0 ;
        int leftH = getHeight(root.left);
        int rightH = getHeight(root.right);
       return leftH>rightH?leftH+1 : rightH+1 ;
    }

    // 检测值为value的元素是否存在
    TreeNode find(TreeNode root, char val) {
        if(root == null) return null ;
         if(root.val == val){
             return root ;
         }
        TreeNode leftNode = find(root.left ,val);
         TreeNode rightNode = find(root.right , val);
         return leftNode != null?leftNode:rightNode;
    }

    //层序遍历1
    public void levelOrder1(TreeNode root){
      if(root == null) return;
      Queue<TreeNode> queue = new LinkedList<>();
      queue.offer(root);
      while(!queue.isEmpty()){
          TreeNode cur = queue.poll();
          System.out.print(cur.val + "  ");
          if(cur.left != null){
              queue.offer(cur.left);
          }
          if(cur.right != null){
              queue.offer(cur.right);
          }
      }
    }
//层序遍历
public List<List<Character>> levelOrder2(TreeNode root) {
    List<List<Character>> list = new ArrayList<>() ;
    if(root == null) return list ;
    Queue<TreeNode> queue = new LinkedList<>() ;
    queue.offer(root);
    while(!queue.isEmpty()){
        int size = queue.size() ;
        List<Character> list2 = new ArrayList<>() ;
        while(size != 0){
            TreeNode tmp = queue.poll();
            list2.add(tmp.val);
            if(tmp.left != null){
                queue.offer(tmp.left);
            }
            if(tmp.right != null){
                queue.offer(tmp.right);
            }
            size-- ;
        }
        list.add(list2) ;
    }
    return list ;
}
    // 判断一棵树是不是完全二叉树
    boolean isCompleteTree(TreeNode root) {
        if(root == null) return true ;
        Queue<TreeNode> queue = new LinkedList<>();
        queue.offer(root);
        while(queue.peek() != null){
            TreeNode cur = queue.poll();
            if(cur != null){
                queue.offer(cur.left);
                queue.offer(cur.right);
            }
        }
        while(!queue.isEmpty()){
            if(queue.poll() != null){
                return false ;
            }
        }
        return true;
    }

}
